This invention relates to a method of manufacturing ornamental and protective edge guards which are applied to the edges of sheet metal panels of automotive vehicles, such as the doors.
Edge guards are applied to the trailing edges of the vehicle's doors to protect the door edges from damage which might be caused by striking an object which may be present in a door's path when the door is opened. It is often desirable for such door edge guards to be made of bright metal such as stainless steel, aluminum, or bimetal, due to the excellent protective and ornamental character of such material. Furthermore, the inherent strength and resiliency of metallic edge guards enable them to be self-retaining on the doors. Correspondingly it is generally undesirable to use separate fasteners or adhesives in securing door edge guards to doors since they involve extra costs in labor and materials. It is also generally undesirable to use strictly non-metallic guards such as plastic edge guards since they do not possess the excellent protective, ornamental, and self-retention characteristics of bright metallic edge guards. In connection with the usage of self-retaining edge guards, it has heretofore been recognized that the potential for paint scratching and marring exists when the metal edge guards are applied to vehicle door edges. Such paint scratching can lead to premature corrosion of the door edge metal.
Some of applicant's inventions have addressed this matter of possible paint scratching and have provided solutions. Applicant has also recognized that electrochemical corrosion is a potential problem where the metal of the vehicle door and the metal of the edge guard are dissimilar. Some of applicant's own inventions have addressed this problem and provided solutions. References made to applicant's U.S. Pat. Nos. 2,704,687 and 4,259,812 as well as pending patent application Ser. Nos. 118,475 now U.S. Pat. No. 4,334,700; 132,525 now U.S. Pat. No. 4,316,340; 194,747 now U.S. Pat. No. 4,338,148; 194,748 now U.S. Pat. No. 4,365,450; 194,749 now U.S. Pat. No. 4,377,056; 216,483; and 216,860 now U.S. Pat. No. 4,387,125.
These prior inventions involve the use of plastic liners to insulate the metal edge guards from the vehicle door. The liners may be extruded plastic, plastic encapsulation, foam plastic, or plastic film by way of example.
In particular, reference is made to pending application Ser. No. 194,747. That application now U.S. Pat. No. 4,338,148 discloses an improvement in a method of manufacturing a door edge guard of the above described type. The invention of that application involves the application of an insulating layer such as a plastic material, to a strip of metal. The laminate thus formed is further processed by roll forming procedures to produce a door edge guard having a generally U-shaped cross section. The insulating layer forms a liner for the interior of the U-shaped section and the bright metal is exposed on the exterior to provide a bright finished appearance; yet the product is possessive of the excellent retention and protective character which are best for use on the edges of swinging closures such as the vehicle's doors. Also disclosed in application Ser. No. 194,747, as well as in certain other of the above identified applications of applicant, is a door edge guard cross section in which the insulating layer is brought around the distal edges of the legs of the U-shaped cross section so as to appear as a thin band on the exterior front edges of the legs. The preferred insulating layer is a dark vinyl. Hence the resultant construction, in addition to its functional attributes, is particularly attractive in that it provides the bright metal appearance in conjunction with a thin dark colored band running along the front edge.
The fabrication of such an insulated metallic door edge guard is particularly convenient in that the layer of insulation is applied to the metal strip before it is roll formed and this saves on having to individually form the liner to a particular cross section separately from the roll forming of the metal strip into the U-shaped cross section.
Applicant has observed that in the manufacture of the type of edge guard containing his earlier invention, a further improvement upon the manufacturing process can be made by including a further layer of lamination with the further layer being applied to the opposite side of the metal strip from that side to which the insulating layer is applied. Hence during the roll-forming procedure all three elements of the lamination, namely the metal strip, the insulating liner and the further layer are all formed to basically the same cross sectional shape. At such a time as desired, for example when the edge guard is put to use, the further layer is stripped from the edge guard to expose the bright metal exterior of the metal strip. Accordingly the further layer serves the purpose of protecting the bright metal of the metal strip during the roll forming process. It can also protect the bright metal during shipment until such time as the edge guard is put to use as installed on a vehicle.
The further layer constitutes a release liner which can be readily removed from the edge guard anytime after manufacture even up to the point at which the edge guard is put to its installed end use. For example a release paper having a release adhesive is a suitable construction for this further release liner. In this way the release paper protects the bright metal against scratching or marring which might otherwise occur during the roll forming process.
The foregoing features, advantages and benefits of the invention, along with additional ones, will be seen in the ensuing description and claims which should be considered in conjunction with the accompanying drawings. The drawings disclose a preferred embodiment of the invention according to the best mode contemplated at the present time in carrying out the invention.